Sealing valve assemblies are utilized to control the flow of pressurized fluids in many high pressure applications. For example, in an aircraft cabin pressure regulation system, a sealing flap valve assembly may be utilized to regulate the flow of pressurized air from the fuselage interior to the ambient environment outside of the aircraft. A representative sealing flap valve assembly includes a valve element that is hingedly mounted within a flowbody and movable between full-open position, a closed position, and various intermediate positions. A wiper seal (e.g., an elongated polymeric strip) is typically affixed to an outer peripheral edge of the valve element. As the valve element moves into the closed position, the wiper seal sweeps across an inner surface of the flowbody to form a seal that substantially prevents the leakage of pressurized fluid past the closed valve element.
In many high pressure applications, it is desirable to enhance the sealing characteristics of a sealing flap valve assembly by spring biasing the wiper seal away from the valve element and into sealing engagement with an inner surface of the flowbody (commonly referred to as “energizing” the wiper seal). In such a case, the wiper seal may be disposed within a slot provided in an outer peripheral portion of the valve element. The wiper seal may slide within this slot between a retracted position and an extended position. A spring, such as a wave spring or a resilient wire form, is further disposed within the slot and compressed between an inner surface of the valve element and the wiper seal. The spring biases the wiper seal away from the valve element and toward the extended position. When the valve element moves into a closed position, the wiper seal sealingly engages the inner surface of the flowbody, which forces the wiper seal toward the retracted position. This further compresses the spring within the slot and thus increases the bias force exerted on the wiper seal by the spring. As a result, the wiper seal forms an enhanced seal with the inner surface of the flowbody across a greater range of the valve element's rotational path.
Although enhancing sealing between the wiper seal and the inner surface of the flowbody, valve assemblies including spring-energized seal mechanisms of the type described above may exhibit with certain limitations. For example, such spring-energized seal mechanisms may be relatively difficult and costly to assemble. The reliability of such a spring-energized seal mechanism may be negatively impacted by high frictional characteristics and stresses, and limited spring life cycles. Furthermore, conventional spring-energized seal mechanisms may not permit the spring bias force exerted on the wiper seal to be adjusted during valve operation.
It should thus be appreciated from the above that it would be desirable to provide a sealing valve assembly, such as a sealing flap valve assembly, having an energized wiper seal that is relatively easy and inexpensive to produce. Preferably, such a sealing valve assembly would minimize frictional stresses and operate in a reliable manner. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.